The present invention relates generally to horizontal underground drilling machines. More particularly, the present invention relates to a vise apparatus used with threaded drill pipe.
A variety of vise arrangements for use with horizontal drilling machines exist, including vise jaws having two opposing jaw halves. The jaws are arranged to clamp onto a pipe to either thread or unthread the pipe to another pipe. The vise jaws are clamped to the pipe by hydraulic actuators or cylinders that provide engagement or clamping force.
In conventional jaw designs, the maximum torque applied to the gripped pipe, without relative movement between the pipe and the jaws, is directly proportional to the force applied by hydraulic cylinders. The torque effected on the pipe provides torque holding capacity at a threaded connection between the two pipes. Larger pipes require greater torque to effect sufficient torque holding capacity. The drill pipe used in conjunction with the conventional jaw design is limited, typically ranging from 1xc2xd to 3xc2xd inches in outer diameter.
Drilling machines utilizing much larger drill pipe and drill tools are becoming available for use in the industry. For example, some drill pipe can range up to about 8 inches in outer diameter. A design that provides greater engagement force to effect sufficient torque holding capacity at a threaded connection between larger pipes is needed.
Conventional designs incorporating a latch door arrangement for use on vertical drilling machines have been used to provide sufficient engagement force on larger diameter pipes. These designs, however, are particular to vertical drilling rigs wherein there is ample space in the vicinity of the latch door vise arrangement. A vise apparatus that accommodates large pipe is needed for use on a horizontal drilling machine where space between the ground and a ground support is limited.
The disclosure describes a vise apparatus for use on a horizontal drilling machine. In one embodiment the vise apparatus includes at least one vise mechanism having scissor members. In another embodiment, the vise apparatus may include two vise mechanisms, each having scissor members.
In the preferred embodiment of the vise mechanisms, the scissor members are components of a linkage arrangement that contacts a clamped element at four locations.
Another aspect of this disclosure involves a vise apparatus that is positionable. In the preferred embodiment, the vise apparatus may be capable of longitudinal translation along rails of a rack assembly. In an embodiment having two vise mechanisms, the second vise mechanism may, in addition, be longitudinally translated along the rails in relation to the first vise mechanism.